ATI 917060 Super Damper Harmonic Balancer for Big Block Chevy 396/402/427

Vehicle Fitment

• Chevrolet Big Block 396 ci (6.5L) -- 1965-1970
• Chevrolet Big Block 402 ci (6.6L) -- 1970-1972
• Chevrolet Big Block 427 ci (7.0L) -- 1963-1969
• GM Performance ZZ572 Crate Engine (OEM equipment)

Fitment Notes

• Fits internally balanced Chevrolet Big Block engines only
• Also fits internally balanced BBC stroker combinations (434, 482, 496, 540, etc.) using 3.76" stroke cranks
• Also fits 366T and 427T tall-deck truck engines (internally balanced, 3.76" stroke)
• Does NOT fit externally balanced engines (454, 502, Gen V/VI BBC)
• Single keyway design -- dual keyway version available as 917060K
• Replaces OEM harmonic balancer/vibration damper
• Designed for high-RPM applications (6,000+ RPM)
• Mounting hardware (crank bolt) not included -- sold separately
• Verify engine balance type before ordering
• Sold individually

Features

• Patented ATI Super Damper -- designed exclusively for high-performance engines
• 2-in-1 elastomer design: 4" inner damper + 7" outer damper in two shells bolted to crank hub
• 3-ring design with eight computer-machined grooves retaining application-specific durometer O-rings
• Dyno-tested O-ring durometers matched to each engine application
• Eliminates torsional crankshaft vibrations for increased horsepower and engine longevity
• SFI 18.1 certified -- proven in Winston Cup and drag racing over 2 million cycles
• CNC-machined steel outer shell with 360° laser-engraved timing marks
• Black zinc chromate finish for corrosion resistance
• Tunable and rebuildable -- install new O-rings to refresh damper performance
• OEM equipment on GM Performance ZZ572 crate engines

Specifications

• Part Number: 917060
• Product Type: Super Damper Harmonic Balancer
• Engine: Chevrolet Big Block (396/402/427) -- internally balanced
• Engine Balance: Internal
• Shell Material: Steel (inner and outer)
• Inertia Weight Material: Steel
• Finish: Black zinc chromate
• Ring Design: 3-ring (eight O-ring grooves)
• Hub Design: One-piece
• Outside Diameter: 7.074 in
• Total Weight: 11.5 lbs
• Inertia Weight: 4.5 lbs
• Keyway Quantity: One
• Degree Markings: Yes -- 360° laser engraved
• SFI Rating: SFI 18.1
• Mounting Hardware Included: No
• Warranty: ATI Performance Products Manufacturer's Warranty
• UPC: 800157031571

Included Components

• 1x ATI 917060 Super Damper harmonic balancer (steel, internally balanced)
• Application-specific durometer O-rings (pre-installed)
• Crank bolt and mounting hardware NOT included -- sold separately

Product Description

The ATI 917060 is a patented Super Damper harmonic balancer designed for internally balanced Chevrolet Big Block 396, 402, and 427 engines. Engineered exclusively for high-performance applications exceeding 6,000 RPM, this damper features a proven 2-in-1 elastomer design that combines a 4" inner damper and 7" outer damper in two CNC-machined steel shells that bolt directly to the one-piece crankshaft hub. The 3-ring inertia weight uses eight precision-machined grooves fitted with application-specific durometer O-rings that are dyno-tested for each engine combination and proven in Winston Cup and drag racing competition over two million cycles. Also compatible with 366T and 427T tall-deck truck engines and aftermarket internally balanced BBC stroker builds using the 3.76" stroke crankshaft. Factory OEM equipment on the GM Performance ZZ572 crate engine. The steel outer shell is finished in durable black zinc chromate and features 360-degree laser-engraved timing marks for precise ignition setup. Total weight is 11.5 lbs with a 4.5 lb inertia weight. Exceeds SFI 18.1 specifications for competition use. Fully tunable and rebuildable by installing new O-rings. Measures 7.074" outside diameter. Not for use with externally balanced engines (454/502). Crank bolt sold separately. Sold individually.